1. Field of the Invention
The present invention relates to an exercise wheel that prevents damage to the torsion springs resulting from operation of the exercise wheel in the wrong direction and that prevents excessive travel thereof.
2. Description of the Related Art
FIGS. 12 and 13 of the drawings illustrates a conventional exercise wheel that includes a housing 1xe2x80x2, two grip rods 2xe2x80x2, a main gear 3xe2x80x2, two roller pairs 4xe2x80x2, and two torsion springs 5xe2x80x2. The housing 1xe2x80x2 includes a compartment with a downwardly facing opening and aligned holes 11xe2x80x2 on two sides thereof into which the grip rods 2xe2x80x2 are mounted. Two stop rods 12xe2x80x2 are mounted inside the housing 1xe2x80x2 . The main gear 3xe2x80x2 is mounted to the grip rods 2xe2x80x2 and includes a hole 32xe2x80x2 on each side thereof. Each roller pair 4xe2x80x2 includes two rollers 41xe2x80x2 connected by a shaft 42xe2x80x2 that has teeth 421xe2x80x2 formed on an outer periphery thereof for meshing with teeth 31xe2x80x2 of the main gear 3xe2x80x2. Each torsion spring 5xe2x80x2 includes two ends 51xe2x80x2 and 52xe2x80x2 that are attached to an associated hole 32xe2x80x2 of the main gear 3xe2x80x2 and an associated stop rod 12xe2x80x2, respectively.
When in use, the user bends downward and grasps the grip rods 2xe2x80x2 to make the roller pairs 4xe2x80x2 to roll on the ground. During rolling of the roller pairs 4xe2x80x2, the torsion springs 5xe2x80x2 are tensioned by the main gear 3xe2x80x2 via transmission of the teeth 421xe2x80x2 and 31xe2x80x2. When the main gear 3xe2x80x2 is turned for one turn, the end 52xe2x80x2 of the torsion spring 51xe2x80x2 bears against the stop rod 12xe2x80x2 and thus stops the main gear 3xe2x80x2 and the roller pairs 4xe2x80x2. The torsion springs 51xe2x80x2 may return the exercise wheel to its initial position.
Nevertheless, when the user operates the main gear 3xe2x80x2 in the wrong direction, the torsion springs 5xe2x80x2 might be damaged, as the torsion springs are twisted in the wrong direction and thus expand radially outward, as shown in FIG. 14.
It is an object of the present invention to provide an exercise wheel that may prevent damage to the torsion springs when the exercise wheel is operated in the wrong direction and that prevents excessive travel thereof.
In accordance with a first aspect of the invention the invention, an exercise wheel comprises:
a housing having two sides;
two grip rods secured to the two sides of the housing, respectively;
a chassis housed by the housing;
a main shaft supported by the chassis;
a main gear mounted around the main shaft;
two wheel assemblies rotatably mounted to the chassis and each including a shaft with a toothed portion for meshing with the main gear; and
two torsion springs mounted around the main shaft and respectively located on both sides of the main gear, each said torsion spring including a first end securely attached to the housing and a second end securely attached to the main gear;
the main gear comprising a peripheral stop surrounding at least one of the torsion springs to thereby avoid radial outward expansion of the torsion springs resulting from movements of the wheel assemblies in a rearward direction.
In accordance with a second aspect of the invention, an exercise wheel comprises:
a housing having two sides;
two grip rods secured to the two sides of the housing, respectively;
a chassis housed by the housing;
a main shaft supported by the chassis;
a main gear mounted around the main shaft;
two wheel assemblies rotatably mounted to the chassis and each including a shaft with a toothed portion for meshing with the main gear; and
two torsion springs mounted around the main shaft and respectively located on both sides of the main gear, each said torsion spring including a first end securely attached to the housing and a second end securely attached to the main gear;
the main gear comprising two free rotating sections such that the main gear rotates freely when the toothed portions of the shafts of the wheel assemblies respectively come in contact with the free rotating sections of the main gear.
In accordance with a third aspect of the invention, an exercise wheel comprises:
a housing having two sides;
two grip rods secured to the two sides of the housing, respectively;
a chassis housed by the housing;
a main shaft supported by the chassis;
a main gear mounted around the main shaft;
two wheel assemblies rotatably mounted to the chassis and each including a shaft with a toothed portion for meshing with the main gear; and
two torsion springs mounted around the main shaft and respectively located on both sides of the main gear, each said torsion spring including a first end securely attached to the housing and a second end securely attached to the main gear;
the main gear comprising two stops that respectively come in contact with the toothed portions of the wheel assemblies for preventing further forward movement of the wheel assemblies after the wheel assemblies have been moved forwardly for a distance.
In accordance with a fourth aspect of the invention, an exercise wheel comprises:
a housing having two sides;
two grip rods secured to the two sides of the housing, respectively;
a chassis housed by the housing;
a main shaft supported by the chassis;
a main gear mounted around the main shaft;
two wheel assemblies rotatably mounted to the chassis and each including a shaft with a toothed portion for meshing with the main gear;
two torsion springs mounted around the main shaft and respectively located on both sides of the main gear, each said torsion spring including a first end securely attached to the housing, a coil portion, and a second end securely attached to the main gear; and
two sleeves respectively mounted around the coil portions of the torsion springs and securely attached to the main gear, each said sleeve comprising a notch through which the second end of a respective said torsion spring extends;
wherein when the exercise wheel moves in a rearward direction, an end edge defining the notch restrains movement of the second end of the respective torsion spring and the sleeve restrains radially outward expansion of the coil portion of the respective torsion spring, thereby preventing damage to the torsion springs.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.